During the first six months of 2013, Washington State patrol’s crime lab said 745 people tested positive for marijuana when, typically, it takes a full year for 1,000 drivers to test positive. A patrol spokesman said that this doesn’t mean there has been a rash of people driving high, just that troopers are looking harder for drivers operating under the influence of pot, and consequently ordering more marijuana blood tests.
In August, the Justice Department announced that it would not sue to block recreational marijuana sales in Washington and Colorado as long as those states satisfy eight federal law enforcement criteria, including keeping pot away from children and off the black market, and work to combat drugged driving.
When Washington and Colorado voters legalized recreational marijuana for 21 and older adults last year, they also set a legal limit of 5 nanograms of active THC per milliliter of blood for drivers. Anything higher is a per-se violation of impaired driving laws. Of the 745 people who tested positive during the first half of this year, 420 tested above the legal limit. 609 drivers tested positive in 2012, up from 506 in 2011. The positive pot-test numbers represent cases handled by the patrol as well as local police agencies.
What the numbers don't reveal is whether more drivers are driving under the influence of marijuana or if police officers are simply testing for marijuana use now that it is legal.